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Y Sawa

Publications and source records attributed to Y Sawa.

At least 127 records · Page 7Linked to original sources
PubMed1998

Gene transfer to vein graft wall by HVJ-liposome method: time course and localization of gene expression.

BACKGROUND: A novel gene transfer method using liposomes with a viral envelope of hemagglutinating virus of Japan (HVJ) has been reported to be very effective for gene transfection into somatic cells and might be applicable to improve the patency of vein grafts. The present study examined the time course and localization of gene expression to assess the feasibility of ex vivo gene transfer into the vein graft by the HVJ-liposome method. METHODS: The HVJ-liposome complex containing either beta-galactosidase plasmid DNA (deoxyribonucleic acid) or no genes (controls) (experiment 1) or fluorescein isothiocyanate-labeled oligonucleotides either with or without HVJ-liposomes (experiment 2) was infused into rabbit vein grafts and allowed to incubate before autologous transplantation to carotid arteries. RESULTS: In experiment 1, all grafts incubated with beta-galactosidase plasmid with HVJ-liposomes showed the blue staining of X-gal 7 days after operation, whereas the controls did not. The blue granules were present in the medial and adventitial tissue and were still present after 14 days. In experiment 2, many fluorescein isothiocyanate-labeled nuclei were observed in the graft wall 2 and 4 days after operation and remained present mainly in the media of HVJ-liposome-treated grafts after 7 and 14 days, when no fluorescein isothiocyanate activity was observed without HVJ-liposome treatment. CONCLUSIONS: These results demonstrated the feasibility of ex vivo transfection to the medial and adventitial tissue of the vein graft by the HVJ-liposome method and suggest the possibility of its clinical application to prevent vein graft failure.

Animals↗
PubMed1998

Off-pump coronary bypass using interposed radial artery graft.

We describe a patient with severely diseased ascending aorta and small internal mammary arteries, who underwent off-pump coronary artery bypass to the left anterior descending coronary artery and right coronary artery using composite arterial grafts consisting of the pedicled proximal internal mammary artery and interposed radial artery graft. The interposed radial artery graft provides advantages, such as making coronary anastomosis on the beating heart easier and to increasing the flow potentiality of the internal mammary artery.

Aged↗
PubMed1998

Interleukin-6 derived from hypoxic myocytes promotes neutrophil-mediated reperfusion injury in myocardium.

BACKGROUND: Reperfusion injury in the myocardium has recently been considered to be a type of inflammation, and close attention has been paid to the possible involvement of neutrophils, complement, and cytokines in the onset of this injury. Recently, it has been reported that serum levels of interleukin-6 are elevated significantly after myocardial infarction. The major site of interleukin-6 production and its exact roles are still unknown. In this study, we hypothesized that myocytes may produce interleukin-6 during hypoxia and this may play a role in neutrophil-mediated reperfusion injury. METHODS AND RESULTS: In the clinical study, 20 patients who underwent coronary artery bypass grafting were divided into 2 groups: group F, in which patients were treated with a serine protease inhibitor (FUT-175, 2 mg/kg per hour) during cardiopulmonary bypass, and group C (untreated patients). In group C, myocardial interleukin-6 production, as determined by the difference between the interleukin-6 level in the cardiopulmonary bypass circuit and its level in coronary venous blood, increased significantly after reperfusion (12+/-4 pg/mL) as compared with that before aortic crossclamping (2+/-2 pg/mL). In group F, the increase in the interleukin-6 level was suppressed significantly (before aortic crossclamping, 3+/-2 pg/mL; after reperfusion, 4+/-3 pg/mL). The interleukin-6 production differed significantly between group C and group F. In the in vitro experimental study, the supernatant from myocytes exposed to 2 hours of hypoxia (group 2H) showed significantly higher levels of interleukin-6 (455+/-260 pg/mL) than that from normoxic myocytes (group N) (47+/-15 pg/mL). This interleukin-6 production was suppressed by the addition of FUT-175 (123+/-24 pg/mL). The interleukin-6 production by endothelial cells of coronary vessels did not differ between group 2H (283+/-151 pg/mL) and group N (151+/-86 pg/mL). In a coincubation system with a monolayer of endothelial cells on collagen membrane and myocytes under collagen membrane in a modified Boyden chamber, 2 hours of coincubation showed a significantly higher percent of neutrophil transendothelial migration (group 2H vs N, 78%+/-13% vs 26%+/-11%), value of chemiluminescence (22+/-8 vs 5+/-2 x 10(3) counts/3 minutes), and percent of irreversibly damaged myocytes (48%+/-17% vs 12%+/-8%) than normoxic coincubation. In contrast, anti-interleukin-6 monoclonal antibody significantly attenuated neutrophil transendothelial migration (42%+/-19%) and irreversible damage of myocytes (26%+/-15%) in 2 hours of coincubation. CONCLUSIONS: Interleukin-6 is produced from myocardium during ischemia and reperfusion in patients undergoing coronary bypass grafting. This interleukin-6 may be derived from hypoxic myocytes and play a role in neutrophil-mediated reperfusion injury in myocardium.

Animals↗
PubMed1998

Immunohistochemical demonstration of lymphatic vessels in human dental pulp.

The existence of lymphatic vessels in dental pulp has been a matter of continuing controversy because of the difficulty of discriminating them in ordinary stained tissue sections. Recently, we have succeeded in establishing a new identification method for lymphatic vessels in human frozen sections by using a commercial monoclonal antibody specific for the human thoracic duct and anti-human laminin antiserum. The present study aimed to examine the lymphatic vessels in human dental pulp using the new immunostaining method, and compared the results with those in human small intestine. The study clearly demonstrated the distribution of lymphatic vessels in human dental pulp. Large lymphatic vessels are located in the central part of the pulp and there are small lymphatic vessels in the periphery of the pulp. This suggests that lymphatic drainage of the human dental pulp starts from the periphery of the pulp and collects in the central part of the pulp. A notable difference between the small intestine and dental pulp was found in the immunoreactivity of lymphatic vessels to anti-human laminin anti-serum. In small intestine, immunoreactivity was significantly weaker than that of the blood vessels, whereas in dental pulp, that of lymphatic vessels was almost the same as blood vessels, except for some lymphatic vessels showing very weak reactivity. These findings suggest that the development of the basement membrane in both the lymphatic and blood vessels of human dental pulp is not as marked as in other tissue.

Adolescent↗
PubMed1998

Lymphatic endothelium expresses PECAM-1.

The expression of adhesion molecules on the lymphatic endothelium of human small intestine and submandibular lymph node was studied immunohistochemically with the antibodies for selectin family and Ig superfamily members. In both small intestine and submandibular lymph node, lymphatic endothelium did not express intercellular adhesion molecule-1 and endothelial cell-selectin but expressed platelet-endothelial cell adhesion molecule-1 (PECAM-1). Though lymphatic vessels may not have a positive function in leukocyte rolling and adhesion, lymphatic endothelium may interact with leukocytes, with PECAM-1 playing a role.

Aged↗
PubMed1998

Vascular endothelium of human dental pulp expresses diverse adhesion molecules for leukocyte emigration.

The expression of adhesion molecules on the vascular endothelium of healthy and inflamed human dental pulp was studied immunohistochemically using antibodies for selectin family and immunoglobulin super-family members. In healthy dental pulp, some vessels reacted very weakly with major histocompatibility complex (MHC) class II, and E- and P-selectin, and many vessels reacted with platelet-endothelial cell adhesion molecule-1 (PECAM-1), but no vessels reacted with intercellular adhesion molecule-1 (ICAM-1), ICAM-3 and vascular cell adhesion molecule-1 (VCAM-1). In inflamed pulp, a large number of vessels reacted strongly with MHC class II, E- and P-selectin, PECAM-1, ICAM-1, ICAM-3, and VCAM-1. This indicates that the vascular endothelium of the inflamed human dental pulp expresses diverse adhesion molecules for leukocyte emigration from the blood stream into tissue. Dental pulp is surrounded by dentin and isolated from other tissue, like an in vitro system, so dental pulp is an attractive model for studying the roles of adhesion molecules on the vascular endothelium in transendothelial migration of leukocytes.

Adolescent↗
PubMed1998

HVJ-liposome mediated gene transfer into hepatocytes in vivo.

BACKGROUND/AIMS: The efficient transduction of appropriate target cells will be critical for gene therapy. We evaluated the suitability of hemagglutinating virus of Japan (HVJ)-liposome-mediated gene transfer for gene therapy of liver diseases. METHODS: The Escherichia coli beta-galactosidase (beta-gal) gene was introduced into rat liver by HVJ-liposome to examine gene transfer efficacy and persistence of expression with or without partial hepatectomy prior to transfection. RESULTS: About 30% of hepatocytes were transduced after portal vein injection. Gene expression was transient, with only 2% of hepatocytes expressing beta-gal after 4 weeks. However, partial hepatectomy performed 24 h prior to injection resulted in persistently high levels of beta-gal for 4 weeks after injection. A 247-bp beta-gal polymerase chain reaction fragment transcript was detected in livers of transfected rats, but not in livers of control rats. The rat livers following gene transfer were histologically normal, and serum glutamic-pyruvic transaminase was not found to be elevated in rats. CONCLUSIONS: Our results demonstrate that HVJ-liposome-mediated gene transfer produced high gene transduction and persistent gene expression in the liver.

Alanine Transaminase↗
PubMed1998

Trimethadione metabolism and microsomal monooxygenases in untreated and phenobarbital-treated rhesus monkeys.

The contribution of induced cytochrome P450 (P450) isozymes (CMLa; CYP2B, CMLb; CYP2A and CMLc; CYP3A) and related enzymes to trimethadione (TMO) metabolism in phenobarbital-treated rhesus monkey were investigated. The animals received a single dose of TMO (4 mg kg-1) and plasma samples were withdrawn before this administration and again at 0.08, 0.25, 0.5, 1 and 2 h later. Phenobarbital-treatment (20 mg kg-1 day-1 for 3 days; i.p.) significantly increased the plasma dimethadione (DMO)/TMO ratios at 0.08, 0.5, 1 and 2 h one's appropriate controls. Phenobarbital treatment also increased the P450 content (1.7-fold) and activity of aniline p-hydroxylase (1.3-fold), p-nitroanisole O-demethylase (1.8-fold) and benzphetamine N-demethylase (2.3-fold). The content of CMLa, CMLb and CMLc were increased about 12.8, 2.3 and 2.7-fold by phenobarbital pretreatment, respectively. The activity of TMO N-demethylation was inhibited by anti-P450 CMLa and anti-P450 CMLb. However, the anti-P450 CMLc antibody had no effect on this activity in liver microsomes. The results of both in vivo and in vitro studies of the effects of phenobarbital treatment on TMO metabolism indicate that these effects may be attributed to the induction of CMLa. These findings suggest that plasma DMO/TMO ratio in a single blood sampling after TMO administration is very useful for determination the degree of hepatic induction in clinical study.

Aniline Hydroxylase↗
PubMed1998

Analysis of the structure and substrate binding of Phormidium lapideum alanine dehydrogenase.

The structure of the hexameric L-alanine dehydrogenase from Phormidium lapideum reveals that the subunit is constructed from two domains, each having the common dinucleotide binding fold. Despite there being no sequence similarity, the fold of alanine dehydrogenase is closely related to that of the family of D-2-hydroxyacid dehydrogenases, with a similar location of the active site, suggesting that these enzymes are related by divergent evolution. L-alanine dehydrogenase and the 2-hydroxyacid dehydrogenases also use equivalent functional groups to promote substrate recognition and catalysis. However, they are arranged differently on the enzyme surface, which has the effect of directing opposite faces of the keto acid to the dinucleotide in each case, forcing a change in absolute configuration of the product.

Alanine↗
PubMed1998

Persistent gene expression in rat liver in vivo by repetitive transfections using HVJ-liposome.

Most viral vectors are highly immunogenic and are of limited use for somatic gene therapy that requires repetitive administrations. We have developed a highly efficient gene transduction procedure useful for repetitive transfections using liposome containing hemagglutinating virus of Japan (HVJ-liposome). The Escherichia coli beta-galactosidase (beta-gal) gene was embodied in HVJ-liposome, and introduced directly into the caudal lobe of rat liver that was transiently isolated from a systemic circulation. A 116 kDa beta-gal protein was detected in transfected rat liver tissues by Western blot analysis and it was expressed in more than two-thirds of the liver by histological staining. It was found that the transfection efficiency was not affected by repetitive transfections. In support of these findings, antibody response to HVJ-liposome detected in the rat sera was weak and transient. Furthermore, cytotoxic T lymphocytes were not elicited against autologous rat hepatocytes that were transfected in vivo using HVJ-liposome. Thus, our results demonstrate that the isolation of a target liver from systemic circulation and the direct administration of foreign genes using HVJ-liposomes are useful for high gene transduction and persistent gene expression in the liver.

Animals↗
PubMed1998

Inhibition of intimal hyperplasia after vein grafting by in vivo transfer of human senescent cell-derived inhibitor-1 gene.

The senescent cell-derived inhibitor (sdi)-1 (p21) protein has been identified as a downstream mediator of the tumor suppressor p53 in the cell cycle regulation. In this study, we focused on the function of sdi-1 gene in inhibiting vascular smooth muscle cell (VSMC) proliferation after vein grafting in a rabbit model. To test the hypothesis, we transfected human sdi-1 gene by an intra-operative approach. Accompanied by markedly increased sdi-1 protein, the significant increase in PCNA-stained VSMCs in vein grafts was inhibited by transfection of sdi-1 gene. Moreover, at 2 weeks after transfection, transfer of sdi-1 gene resulted in a significant inhibition in neointimal formation, compared with control vector. Of importance, immunohistological studies determining the expression pattern of myosin heavy isoforms, adult type specific SM2 and embryonic specific SMemb/NMHC-B, demonstrated expression of the adult phenotype of VSMCs in the neointima of sdi-1 gene-transfected vein grafts at 2 weeks after the operation, while the neointima was predominantly composed of embryonic phenotype of VSMCs in the control grafts. Overall, these results demonstrate that a single intraluminal incubation of human sdi-1 gene can result in a significant inhibition of neointimal formation after vein grafting, associated with phenotypic change of VSMCs from neonatal to adult type in a rabbit model. Inhibition of hyperplasia in a graft model by transfection of sdi-1 gene may be due to the change in VSMC phenotype from neonatal to adult, in addition to the inhibition of VSMC growth.

Actins↗
PubMed1998

Efficient transfer of oligonucleotides and plasmid DNA into the whole heart through the coronary artery.

Several of the current techniques for transfer of both oligonucleotide and plasmid DNA into the myocardium are impaired by low efficiency and toxicity. To improve gene transfer techniques, especially into the whole heart, a gene transfer method involving liposome in conjunction with a viral envelope (HVJ-liposome) was essayed as an alternative. FITC-labeled oligonucleotide (F-ODN) and the cDNA of beta-galactosidase (beta-gal) were introduced into the myocardium by coronary infusion of HVJ-liposome during cardioplegic arrest of adult Sprague-Dawley rat hearts. Then, transfected heart was ectopically transplanted into another rat abdomen of the same strain to maintain the transfected heart long enough to allow for protein synthesis. After 3 days of transfection, transfected heart was excised and the efficiency of gene transfection was evaluated. FITC was detected in the nuclei of more than 70% of the myocytes and endothelial cells both in the epicardium and endocardium. beta-Gal was expressed in the cytosol of more than 50% of the myocytes. beta-Gal expression was demonstrated by Western blotting analysis at day 3 after transfection and continued for at least 14 days. No significant histological damage of the myocardium or leakage of CPK were detected in the rats transfected by the HVJ-liposome method. These results clearly demonstrate that the hearts were efficiently transfected both by oligonucleotide and plasmid DNA as a result of coronary infusion of HVJ-liposome during cardioplegic arrest. This thus appears to be an efficient method for gene transfer into the whole heart, providing a new tool for research and therapy for heart diseases.

Animals↗
PubMed1998

A novel technique for cardiopulmonary bypass using vacuum system for venous drainage with pressure relief valve: an experimental study.

To decrease the circuit priming volume, develop safety, and simplify the equipment, a cardiopulmonary bypass (CPB) circuit using a vacuum suction venous drainage system with a pressure relief valve was developed. The efficacy of this vacuum system was compared to that of a conventional siphon system. The system contains a powerful vacuum generator and a pressure relief valve to keep the negative pressure constant when blood suction is used. Using 8 mongrel dogs, the feasibility and the efficacy of this CPB system was tested. The changes in the negative pressure in the reservoir were within 5 mm Hg whether the suction lines were switched on or off. In all animals the amount of blood in the venous reservoir was stable throughout bypass. The decrease of priming volume was from 725 ml (siphon system) to 250 ml (vacuum system). At the end of CPB, the levels of hemoglobin in the vacuum system were significantly higher than those in the siphon system. These results demonstrated that this vacuum drainage system can provide simplification and a miniaturization of the cardiopulmonary bypass circuit resulting in low hemodilution during CPB.

Animals↗
PubMed1998

Minimally invasive cardiac surgery: current status and perspective.

Recently, the minimally invasive approach has become a growing aspect in the field of cardiac surgery with the goal of eliminating cardiopulmonary bypass (CPB) and/or median sternotomy. In coronary bypass surgery, the application of this approach is direct anastomosis, primarily of the left internal thoracic artery to the left descending coronary artery under a beating condition without the use of CPB through a small left thoracotomy minimally invasive direct coronary artery bypass (MIDCAB). In the repair of intracardiac lesions, CPB cannot be excluded, but a small right parasternal incision or small partial sternotomy (ministernotomy) has been applied for congenital defects and mitral and aortic valve lesions. With technological advances in CPB, these approaches may become more popular in the near future.

Anastomosis, Surgical↗